J-FLOW on ERX310.

Hi Can Any one help me in understanding J-Flow functionality on ERX310?

My Requirement is: I am using C-VLAN model on the access device for unicast traffic and one common multicast VLAN for all multicast traffic,so that each BHR/home will have one VLAN for each BHR for all unicast traffic.

Now All services like IPTV, VoD, VoIP, Internet will through C-VLAN for unicast traffic and IPTV will flow through multicast traffic.

As the traffic is flowing through same VLAN,how can start billing for only for Internet usage only? As the unicast VLAN will carry unicast VoD traffic, unicast VoIP traffic, Unicast Internet traffic.